Hemitaurichthys polylepis (Bleeker 1857)

The pyramid butterflyfish (Hemitaurichthys polylepis) is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae, native from central Indo-Pacific.

Description

The pyramid butterflyfish is a small-sized fish that can reach a maximum length of 18 cm.^[3]

Its body is compressed laterally with a rounded body profile, and its snout protrudes forwards slightly with a small protrusible (extendable) mouth. Its very characteristic livery leaves no doubt about the identification. A dark brown-yellow area, the colour of which may vary in intensity, fully masks the head and extends to a line from the first rays of the dorsal fin to the start of its pelvic fins.^[4]

The rest of its body is white, peduncle and caudal fin included. Insertion of yellow-orange areas at the top of the side form a characteristic pyramidal pattern, hence the name of the fish.^[5] The anal fin is also yellow-orange.^[4]

Distribution and habitat

The pyramid butterflyfish is widespread throughout the tropical and subtropical waters of the central Indo-Pacific from Cocos Keeling and Christmas Island to Polynesia and from south Japan to New-Caledonia. ^{[1] [6]}

The pyramid butterflyfish appreciates the outer reef slopes from which it can swim out into open water to get its food. It can be seen at depths from 3 to 60 meters deep.^[7]

Biology

The pyramid butterflyfish lives in large schools, and feeds on plankton in open water out of its shelter reef.^[8]

Conservation status

The species as a planktivorous could be affected by climate-induced reductions in planktonic productivity. There do not appear to be any current threats to this species and it is listed as Least Concern (LC) by the IUCN.^[1]

References